Scientists Say Risk of 5 Climate Tipping Points Means 'Business as Usual Is Now Over'

An earlier version of this article said the sea levels could rise by 656 feet by 2100 if the Antarctic ice sheet started to melt. It has been corrected to reflect the fact that they would rise by 6.6 feet.

Current levels of global heating from the burning of fossil fuels and the destruction of nature risk triggering five tipping points that could throw Earth's systems further out of balance, with three more at risk of toppling in the next decade.

The Global Tipping Points Report, released Wednesday at the United Nations Climate Change Conference (COP28) in the United Arab Emirates, argues that policymakers have delayed climate action long enough that "linear incremental change" will no longer be enough to protect ecosystems and communities from the worst impacts of the climate crisis. However, world leaders can still choose to take advantage of positive tipping points to drive transformative change.

"The existence of tipping points means that 'business as usual' is now over," the report authors wrote. "Rapid changes to nature and society are occurring, and more are coming."

"Crossing these thresholds may trigger fundamental and sometimes abrupt changes that could irreversibly determine the fate of essential parts of our Earth system for the coming hundreds or thousands of years."

The report defines a "tipping point" as "occurring when change in part of a system becomes self-perpetuating beyond a threshold, leading to substantial, widespread, frequently abrupt and often irreversible impact." A group of more than 200 researchers assessed 26 different potential tipping points in Earth's systems that could be triggered by the climate crisis.

"Tipping points in the Earth system pose threats of a magnitude never faced by humanity," report leader Tim Lenton of Exeter's Global Systems Institute said in a statement. "They can trigger devastating domino effects, including the loss of whole ecosystems and capacity to grow staple crops, with societal impacts including mass displacement, political instability, and financial collapse."

Because current emissions trajectories put the world on track for 1.5°C of warming, this is likely to trigger five tipping points, the report authors found. Those tipping points are the melting of the Greenland and Antarctic ice sheets, the mass die-off of warm-water coral reefs, the thawing of Arctic permafrost, and the collapse of the North Atlantic Subpolar Gyre circulation.

The melting of just the Antarctic ice sheet, for example, could raise global sea levels by 6.6 feet by 2100, Carbon Brief reported, meaning 480 million people would face yearly coastal flooding. Three more tipping points could be triggered in the 2030s if temperatures rise past 1.5°C. These include the mass death of seagrass meadows, mangroves, and boreal forests, according to The Guardian.

"Crossing these thresholds may trigger fundamental and sometimes abrupt changes that could irreversibly determine the fate of essential parts of our Earth system for the coming hundreds or thousands of years," co-author Sina Loriani of the Potsdam Institute for Climate Impact Research told The Guardian.

Contributor Manjana Milkoreit of the University of Oslo said in a statement that "our global governance system is inadequate to deal with the coming threats and implement the solutions urgently required."

But that doesn't mean the report authors believe that hope is lost. Rather, they see it as a call to ambitious action at the current U.N. climate talks and beyond.

"Averting this crisis—and doing so equitably—must be the core goal of COP28 and ongoing global cooperation," Milkoreit said.

One way to do this is to take advantage of positive tipping points.

"Concerted actions can create the enabling conditions for triggering rapid and large-scale transformation," the report authors wrote. "Human history is flush with examples of abrupt social and technological change. Recent examples include the exponential increases in renewable electricity, the global reach of environmental justice movements, and the accelerating rollout of electric vehicles."

The report authors made six recommendations based on their findings:

1. Immediately phasing out fossil fuels and emissions from land use changes like deforestation;
2. Strengthening plans for adaptation and loss and damage in the face of inevitable tipping points;
3. Taking tipping points into account in Paris agreement mechanisms like the global stocktake and national climate pledges;
4. Collaborating to trigger positive tipping points;
5. Organizing a global summit on tipping points; and
6. Increasing research on tipping points, including through a special report by the Intergovernmental Panel on Climate Change.